Spindle motor with shell for solid-plate running gears

ABSTRACT

The invention relates to a spindle motor for solid-plate running gears with a stator, a rotor, the shaft of which is turnably borne with the aid of rolling bearings with respect to the stator, and a shell, in which the shell is constructed as a separate pot-shaped part closed on one side, on the outer circumference of which the stator is held and on the inner circumference of which the outer rings of the rolling bearings are held.

[0001] The invention relates to a spindle motor for solid-plate running gears, in particular a spindle motor with shell according to the generic term of patent claim 1.

[0002] In general spindle motors comprise a stator and a rotor turnably borne about a central shaft with respect to this. The bearing occurs by means of rolling bearings, in which the shaft is either joined in fixed position with the stator, or is turnably borne together with the rotor.

[0003] In particular, the invention relates to so-called base-plate or basis-plate motors of the last-mentioned type, consisting of rotor, stator and basis plate, in which the shaft firmly joined with the rotor is turnably borne with the aid of rolling bearings with respect to the stator fastened indirectly or directly to the basis plate. The outer, fixed parts of the roller bearings, therefore the outer rings, are fastened there ordinarily in a shell (Hülse) open at both ends, which is either an internal component of the basis plate or is installed in this as a separate member. The outward-directed opening of the shell is covered off and sealed gas-tight.

[0004] A disadvantage of the construction described is that for the covering-off of the shell opening an additional part is needed, the hermetic sealing-off of which, preferably by means of a liquid sealing agent (bonding agent) is functionally critical, expensive and time-consuming.

[0005] Further disadvantages lie in that motor-relevant parameters are checkable only after the mounting of the rotor in the basis plate on the fully assembled motor, so that possible faults cannot be detected until this stage, in which the mounting of the rotor in the basis plate is rendered difficult by magnetic forces and moments.

[0006] The problem of the invention lies in improving a spindle motor with shell for solid-plate running gears in such manner that, on the one hand, the sealing problems addressed above are eliminated and, on the other hand, a more advantageous assembling and testability of the motor are given.

[0007] This problem is solved by the features of patent claim 1.

[0008] The invention is distinguished by the separate pot-shaped shell closed on one side, on the outer circumference of which the stator is held, and on the inner circumference of which the outer rings of the rolling bearings are held. The shell serves, therefore, as assembling aid for the rolling bearings and for the stator.

[0009] By reason of the feature that on the outer circumference of the pot-shaped shell the stator is held, and on the inner circumference the rolling bearings are held, the motor can already be completed in the basis plate and tested before the end of its construction.

[0010] There, with the mounting of the thus prefabricated unit into the basis plate, no hampering magnetic forces arise.

[0011] Further, there is the additional advantage that the member required for the covering-off of the shell opening is eliminated, and the sealing-off of the fit between shell and basis plate can be done very much more simply.

[0012] Advantageous further developments and modifications of the invention are yielded from the dependent claims.

[0013] It is provided, accordingly, that the shell consists of a plastic material. This offers the advantage that a noise damping takes place. Since the shell according to the invention surrounds the ball bearings radially externally, the noises that proceed from the bearings are damped.

[0014] It is just as possible, of course, to make the shall of metal or of a metal alloy.

[0015] As an assembling aid for the stator, the shell can have a step or a collar on its upper open end, on which the stator bears.

[0016] For the reception of the motor, on the basis plate there is provided a corresponding interruption into which the shell is installed true to measure, and fastened by a preferably sealing cementing. After installation ofthe motor into the basis plate, the interruption is closed from the bottom of the shell. A sealing of the fitting joint between shell and basis plate prevents the penetration of contaminated air from the environment into the interior of the solid-plate running gears. Simultaneously the bearing system is bounded by the base integrated into the shell, so that no dirt particles can force their way from the outside into the bearing system.

[0017] The inventive object of the present invention is yielded not only from the object of the individual patent claims, but also from the combination of the individual patent claims among one another. All of the data and features disclosed in the documents, inclusive of the abstract, especially the spatial construction shown in the drawing, are claimed as essential to the invention insofar as, individually or in combination, they are novel with respect to the state of the art.

[0018] In the following, the invention is explained in detail with the aid of a drawing showing several forms of execution. Here from the drawing and its description, there proceed further features and advantages of the invention.

[0019] In the drawing:

[0020]FIG. 1 shows a section through a first form of execution of the spindle motor with shell,

[0021]FIG. 2 a section through a second form of execution of the spindle motor with shell,

[0022]FIG. 3 a section through a third form of execution of the spindle motor with shell,

[0023]FIG. 4 a section through a spindle motor with shell according to the state of the art.

[0024] In all the figures described in the following the like members are provided with the same reference number, so that a separate description of its own for each figure can be dispensed with

[0025]FIG. 4 shows a spindle motor for solid-plate running gears according to the state of the art. The spindle motor comprises an about bell-shaped rotor 1, which is untwistably joined with a shaft 12. The shaft 12 is borne by means of rolling bearings 2 and 6 in a sleeve-form projection 17 of the basis plate 18. To the outside of the sleeve-form projection 17 a stator 5 is fastened. The outward-directed opening ofthe basis plate 18 or of the sleeve-form projection 17 is covered by means of a covering 19 and sealed gastight.

[0026] As is yielded from FIGS. 1 to 3, the spindle motor of the invention likewise comprises an about bell-shaped rotor 1, which is joined untwistably with a shaft 12.

[0027] This is an about pot-shaped shell 1, closed on one side, and opened upward, to the inside of which there are fastened the outer rings 3 and 7, respectively, ofthe rolling bearings 2 and 6. The corresponding inner rings 4 and 8 of the rolling bearings 2 and 6, respectively, are fastened to the shaft 12. Between the corresponding outer and inner rings 3, 4 and 7, 8, respectively, rolling bodies are arranged, so that the unit of rotor 1 and shaft 12 is turnably borne with respect to the stationary shell 11.

[0028] The stator 5 consisting of metal stack provided with coils is arranged on the outer circumference of the shell 11 and firmly joined with this. The stator 5 stands in functional connection with a permanent magnet 9 fastened in the rotor 1 and spaced with respect to the stator 5 in such manner that by corresponding current supplying of the coils an electromagnetic field is generated, the torque of which sets into rotation the unit consisting of rotor 1, shaft 12 and permanent magnet 9.

[0029] The shell 11 itself is received firmly in a central interruption of the basis plate 10. The basis plate 10 comprises the further electrical connection arrangements 16, over which the windings of the winding back are supplied with current.

[0030] The sleeve 11 consists preferably of a plastic material, but it can just as well consist of a metal material.

[0031] As one perceives in FIGS. 1 and 2, the shell 11 can have a step 14 on the upper open zone, which serves as stop and assembling aid for the stator 5. In FIG. 3 there is formed, instead of the step, a collar 16 which fulfills the same function.

[0032] All the forms of execution have in common the feature that the shell serves as an assembling aid in the composition of the spindle motor and makes possible a function test of the spindle motor before the final assembly.

[0033] In the assembling of the motor, first the lower bearing 6 is installed in the shell 11. Then the spacer 13 is mounted and subsequently the upper bearing 2. Thereupon the unit consisting of shaft 12 and rotor 1 is installed and centered in correct position to the shell 11. Finally the stator 5 is mounted on the outer circumference of the shell 11.

[0034] Already in the assembling stage the motor is capable of running and can be tested in respect to the motor-specific parameters.

[0035] It is only after the testing cycle that the motor is installed in the basis plate 10, as the shell 11 is installed beside the stator 5 with its attachment parts in the interruption of the basis plate 10, that is provided, there fixed in proper position and cemented.

REFERENCE NUMBERS OF THE DRAWINGS

[0036] 1 Rotor

[0037] 2 Rolling bearing (above)

[0038] 3 Outer ring

[0039] 4 Inner ring

[0040] 5 Stator (winding pack)

[0041] 6 Rolling bearing (below)

[0042] 7 Outer ring

[0043] 8 Inner ring

[0044] 9 Magnet

[0045] 10 Basis plate

[0046] 11 Shell

[0047] 12 Shaft

[0048] 13 Spacer

[0049] 14 Step

[0050] 15 Collar

[0051] 16 Connection arrangements

[0052] 17 Sleeve-form projection

[0053] 18 Basis plate

[0054] 19 Covering 

1. Spindle motor for solid-plate running gears with a stator (5) stationary with respect to a basis plate (10), a rotor (1), the shaft (12) of which, with the aid of rolling bearings (2, 6), is turnably borne with respect to the stator (5), and a shell (11), characterized in that the shell (11) is constructed as a separate pot-shaped part closed on one side, on the outer circumference of which shell the stator (5) is held and on the inner circumference of which the outer rings (3, 7) of the rolling bearings are held.
 2. Spindle motor according to claim 1, characterized in that the shell (11) consists of plastic material.
 3. Spindle motor according to claim 1, characterized in that the shell (11) consists of metal or of a metal alloy.
 4. Spindle motor according to one of the preceding claims, characterized in that the shell (11) has on its upper open end a step (14) or a collar (15) as assembling aid for the stator (5).
 5. Spindle motor according to one of the preceding claims, characterized in that the shell (11) is firmly joined with the basis plate (10).
 6. Spindle motor according to claim 5, characterized in that the connection between shell (11) and basis plate (10) is a bonding connection. 